Evolution of digestive enzyme genes associated with dietary diversity of crabs

How to become a crab: Phenotypic constraints on a recurring body plan

“…The functional relationship between carcinized forms and shell-crushing is diluted by the presence of mineralized, asymmetrical, and ornamented claws and crushing mandibles in other decapods, such as lobsters, [5,70] and by varied crab diets including herbivory. [70,[78][79][80] Of the carcinized anomurans, only porcelain crabs (Figures 2H, 3B) have a known Mesozoic fossil record. [11,81] Although porcelain crabs and L. hirta (Figure 2J) have broad claws, these taxa are mainly filter feeders, occasionally using their claws to scrape algae.…”

How to Become a Crab: Phenotypic Constraints on a Recurring Body Plan

“…Therefore, many taxa bearing large, ornamented, and mineralized claws are not predators. The functional relationship between carcinized forms and shell-crushing is diluted by the presence of mineralized, asymmetrical, and ornamented claws and crushing mandibles in other decapods, such as lobsters (Schweitzer and Feldmann 2010;Scholtz 2014), and by varied crab diets including herbivory (Schweitzer and Feldmann 2010;Boudreau and Worm 2012;Poore et al 2017;Wang et al 2020). Of the carcinized anomurans, only porcelain crabs ( Figure 2H) have a known Mesozoic fossil record (Robins and Klompmaker 2019;Wolfe et al 2019).…”

Trophic shift and the origin of birds

“…The higher the nutrient substrate, the higher the expression and activity of its corresponding digestive enzymes and nutrient transporters and vice versa (Karasov et al 2011;Karasov and Douglas 2013). This suggests that the digestion and absorption capability of animals is under evolutionary adaptation to approximately match loads of different dietary components such as carbohydrates, proteins and fats in their diets (Schondube et al 2001;Karasov et al 2011;Karasov and Douglas 2013;Wang et al 2016c;Hecker et al 2019;Wang et al 2020). With this in mind, one would expect that herbivores and carnivores would tend to present an evolutionary enhancement of the digestion and absorption of plant food and meat, respectively.…”

“…Regarding plant food and meat (including both invertebrates and vertebrates), one of the important differences between them is that meat is generally high in proteins and fats, while plant food is generally high in carbohydrates (Clinic 2002;Karasov et al 2011;Chen and Zhao 2019;Hecker et al 2019;Wang et al 2020) except seeds, particularly nuts, which are rich in fat as well (Clinic 2002). Indeed, recent studies on the evolution of digestive systemrelated genes have shown that carnivores more likely show an evolutionary enhancement of the genes related to the digestion and absorption of proteins and fats, while animals consuming abundant plant foods (e.g., herbivores and omnivores) tend to exhibit an evolutionary enhancement of the genes related to the digestion and absorption of carbohydrates (Chen and Zhao 2019;Wang et al 2020;Wu et al 2020), with the exception of parrots, which ingest seeds and nuts and present an evolutionary enhancement of the digestion and absorption of fat in addition to carbohydrates (Wu et al 2020). This may suggest that the adaptive evolution of digestive system-related genes is capable of reflecting the dietary variations of different animals (Chen and Zhao 2019;Wang et al 2020;Wu et al 2020).…”

“…The recent development of a molecular phyloecological approach, which employs the phylogenetic evolutionary analyses of the molecular markers indicative of trait states, allows us to reconstruct ancestral traits using molecular data (Wu et al 2017;Wu et al 2018;Wu and Wang 2019). The substantial dietary differences between carnivores and herbivores in terms of the amounts of dietary components (e.g., carbohydrates, proteins, and fats) (Clinic 2002;Karasov et al 2011;Hecker et al 2019;Wang et al 2020), and the adaptation of digestive system-related genes to the variations of dietary components of animals (Schondube et al 2001;Karasov et al 2011;Karasov and Douglas 2013;Wang et al 2016c;Hecker et al 2019;Wang et al 2020;Wu et al 2020) may suggest that digestive system-related genes can be used as the molecular markers of diets to reconstruct the diets of ancestral animals in the context of molecular phyloecology (Wu et al 2020). In this study, we employed the molecular phyloecological approach using digestive system-related genes as molecular markers to infer the diets of the ancestral archosaur and of the common ancestor of living birds (CALB).…”